How do I unlock Scotland, Medieval 2 Total War, WITHOUT cheats?

I really don't want to dabble in the code, I'm a programmer and it I sure as hell wouldn't want some 12 year old dabbing in my code, no offense to 12 year olds... Do I wipe them off the map? I already did that, I played the long campaign and wiped out every nation besides Mongols and Timurids. How do I do so?